As part of the Coastal Sediment Availability and Flux and Defense Advanced Research Protection Agency (DARPA) Reefense projects, scientists from the U.S. Geological Survey (USGS) and St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted a nearshore geophysical survey to map and characterize the stratigraphy of back-barrier bays near Panama City, Florida (FL) in June 2022. This data release serves as an archive of sediment vibracores collected from St. Andrew Bay, April 23–27, 2023. Sediment vibracore and lithology data provide assessments on the composition and age of sediments below the seafloor. This information can provide information about sub-seafloor structure that can inform the siting and assess the stability of artificial and natural oyster reef structures that will be placed on the seafloor during the Reefense project’s later phases.

The following report summarizes the dating results from Aeolian deposits within and around Edwards Air Force Base in California. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.

The following report summarizes the dating results from Aeolian deposits within and around Edwards Air Force Base in California. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.

This report details the luminescence ages and characteristics of four (4) samples that were collected by Jessica Jobe and Rich Briggs of the USGS. These samples are from Holocene and Pleistocene sediments offset by a fault that is exposed in a road cut. The roadcut is in Puerto Rico at 18.003828 and -67.140249 with an elevation of 13.5 m. The sample depths from the modern surface varied from 0.6 m (top) for GB-OSL-4 to 1.6 m for GB-OSL-2 (deepest sample).

This data release contains luminescence data from the manuscript "Application of a luminescence-based sediment transport model" by Gray et al. It contains data from the luminescence measurements and experiments in the paper.

Several historic, multi-fault ruptures in the Eastern California Shear Zone (ECSZ) reinforce the need to understand how this rupture style contributes to seismic hazard in complex and diffuse fault zones. Several historic earthquakes in the ECSZ, the 1992 Landers, the 1999 Hector Mine, and the 2019 Ridgecrest rupture sequence, involved complex and multi-fault rupture. However, paleoseismic evidence of multi-fault ruptures in the ECSZ is poorly resolved in the rock record. Here I investigate paleoseismic evidence for complex rupture in Panamint Valley, located ~50 km northeast of the 2019 Ridgecrest ruptures. Late Holocene scarps in the 10 km-wide transtensional relay between the Ash Hill and Panamint Valley faults display surface rupture geometries analogous to those produced during the 1992 Landers and 1999 Hector Mine earthquakes. I produce a 1:4000 scale tectonogeomorphic map of the 40 km² area between the Ash Hill and Panamint Valley faults using my locally-calibrated relative-age alluvial fan chronology and using NCALM lidar DEMs and aerial imagery to identify ruptures. I bracket earthquakes with post-IR feldspar infrared-stimulated luminescence dating of offset deposits. I record vertical and lateral offsets at over 250+ locations using field mapping and backslipped reconstructions of newly generated high resolution (5 cm) drone-based structure from motion digital surface models. My mapping shows that the transtensional relay consists of 100+ fault strands that occur in parallel and en échelon arrays 5-7 km in length, with spacings of 1s to 100s of meters. Using my relative-age fan stratigraphy, geochronologic dating of offset deposits, and relative cumulative offset, I identify four late Holocene ruptures at ~0.3 – ~0.7 ka, ~0.7 – 2.4 ka, ~2.6 – 3.6 ka, and ~3.6 – 4.2 ka. Displacement magnitude per event ranges from 0.6 – 1.0 m of lateral slip and 0 – 0.2 m of dip slip. Displacement-length scaling relationships suggest that these mapped faults cannot rupture independently of a larger fault system. My results show overlap in the timing of ruptures in the transtensional relay, on the Ash Hill and Panamint faults, and that the Ash Hill and transtensional relay are kinematically similar. These similarities suggest this region acts as a zone for complex strain transfer between the Ash Hill and Panamint faults over multiple earthquake cycles. These relationships may support a geometric link at depth or the reoccupation of preexisting weaknesses at depth capable of transferring strain over larger distances.

Several historic, multi-fault ruptures in the Eastern California Shear Zone (ECSZ) reinforce the need to understand how this rupture style contributes to seismic hazard in complex and diffuse fault zones. Several historic earthquakes in the ECSZ, the 1992 Landers, the 1999 Hector Mine, and the 2019 Ridgecrest rupture sequence, involved complex and multi-fault rupture. However, paleoseismic evidence of multi-fault ruptures in the ECSZ is poorly resolved in the rock record. Here I investigate paleoseismic evidence for complex rupture in Panamint Valley, located ~50 km northeast of the 2019 Ridgecrest ruptures. Late Holocene scarps in the 10 km-wide transtensional relay between the Ash Hill and Panamint Valley faults display surface rupture geometries analogous to those produced during the 1992 Landers and 1999 Hector Mine earthquakes. I produce a 1:4000 scale tectonogeomorphic map of the 40 km² area between the Ash Hill and Panamint Valley faults using my locally-calibrated relative-age alluvial fan chronology and using NCALM lidar DEMs and aerial imagery to identify ruptures. I bracket earthquakes with post-IR feldspar infrared-stimulated luminescence dating of offset deposits. I record vertical and lateral offsets at over 250+ locations using field mapping and backslipped reconstructions of newly generated high resolution (5 cm) drone-based structure from motion digital surface models. My mapping shows that the transtensional relay consists of 100+ fault strands that occur in parallel and en échelon arrays 5-7 km in length, with spacings of 1s to 100s of meters. Using my relative-age fan stratigraphy, geochronologic dating of offset deposits, and relative cumulative offset, I identify four late Holocene ruptures at ~0.3 – ~0.7 ka, ~0.7 – 2.4 ka, ~2.6 – 3.6 ka, and ~3.6 – 4.2 ka. Displacement magnitude per event ranges from 0.6 – 1.0 m of lateral slip and 0 – 0.2 m of dip slip. Displacement-length scaling relationships suggest that these mapped faults cannot rupture independently of a larger fault system. My results show overlap in the timing of ruptures in the transtensional relay, on the Ash Hill and Panamint faults, and that the Ash Hill and transtensional relay are kinematically similar. These similarities suggest this region acts as a zone for complex strain transfer between the Ash Hill and Panamint faults over multiple earthquake cycles. These relationships may support a geometric link at depth or the reoccupation of preexisting weaknesses at depth capable of transferring strain over larger distances.

This dataset includes optically stimulated luminescence (OSL) age data from sediment cores collected offshore central California in the vicinity of Morro Bay. These data were collected aboard the M/V Bold Horizon in October 2019 for use in regional hazard assessments relating to the Hosgri Fault.

This dataset includes optically stimulated luminescence (OSL) age data from sediment cores collected offshore central California in the vicinity of Morro Bay. These data were collected aboard the M/V Bold Horizon in October 2019 for use in regional hazard assessments relating to the Hosgri Fault.

Deep Springs Valley (DSV) is a hydrologically isolated valley between the White (north and west) and Inyo (south and east) Mountains that is commonly excluded from regional paleohydrologic and paleoclimate studies. Previous studies showed that uplift of Deep Springs ridge (informal name) by the Deep Springs fault defeated streams crossing DSV and hydrologically isolating the valley sometime after eruption of the Bishop Tuff. Here we present tephrochronology, clast counts, paleontology, and infrared stimulated luminescence (IRSL) data that reaffirms interruption of the Plio-Pleistocene hydrology and formation of DSV during the Pleistocene. Fossil gastropod, ostracodes, and charophytes along with IRSL dating document the 83.3-61.5 ka freshwater Deep Springs Lake, which roughly coincides with 71-57 ka Marine Isotope State 4 (MIS 4) glacial climate period. Documentation of the MIS-4 glacial climate in southwestern North America is sparse and pluvial Deep Springs Lake is indirect evidence of the MIS 4 glaciation that is corroborated by pluvial lakes in nearby Owens and Searles Valleys. We hypothesize that the MIS-4 Deep Springs Lake overflowed into Eureka Valley via the Soldier Pass wind gap. Hydrologic evolution of DSV has potential implications for understanding Pliocene and Pleistocene biotic dispersal pathways and endemism.